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How a century of ammonia synthesis changed the world
On 13 October 1908, Fritz Haber led his patent on the synthesis of ammonia from its elements for which he was later awarded the 1918 Nobel Prize in Chemistry. A hundred years on we live in a world transformed by and highly dependent upon HaberBosch nitrogen.
Although over 78% of the atmosphereis composed of nitrogen, it exists in its chemically and biologically unusable gaseous form. Haber discovered how ammonia, a chemically reactive, highly usable form of nitrogen, could be synthesized by reacting atmospheric dinitrogen with hydrogen in the presence of iron at high pressures and temperatures. Today, this reaction is known as the HaberBosch process: Fritz Haber was the inventor who created the breakthrough and laid the foundations for high-pressure chemical engineering, but it was Carl Bosch who subsequently developedit on an industrial scale, for which hewas awarded a Nobel Prize in 1931. The importance of Habers discovery cannotbe overestimated as a result, millions of people have died in armed conicts over the past 100 years, but, at the same time, billions of people have been fed.
In his Nobel lecture, Haber explained that his main motivation for synthesizing ammonia from its elements was the growing demand for food, and the concomitant need to replace the nitrogen lost from elds owing to the harvestingof crops: it was clear that the demandfor xed nitrogen, which at the beginning of this century could be satised with a few hundred thousand tons a year, must increase to millions of tons1. We now know that his vision was right: the current worldwide use of fertilizer nitrogen is about 100 Tg N per year.
Habers other motivation, not mentioned in his lecture, was to provide the raw material for explosives to be used in weapons, which requires large amounts of reactive nitrogen. Habers discovery has therefore had a major inuence on both World Wars and all subsequent conicts. In addition, the large-scale productionof ammonia has facilitated the industrial manufacture of a large number of chemical compounds and many synthetic products. Th us the HaberBosch process, with its impacts on agriculture, industry
and the course of modern history, has literally changed the world.
What Fritz Haber could notforesee, however, was the...